A complete register of all new cancer cases diagnosed in the resident population of several standard metropolitan statistical areas and two states during the period 1969-1971 has been developed and analyzed to determine the incidence of cancer classified according to demographic characteristics of the patient as well as characteristics of the tumor. For a 10% sample of patients in the register, additional information was obtained regarding treatment of the disease, economic costs, personal habits, and occupation. Total hospitalizations per patient during a two-year follow-up period averages 28.2 days with an average hospital payment of $2,529. Among whites, negative associations between both income and education with the incidence of cancers of the esophagus, stomach, rectum, lung, uterine cervix, and chronic lymphocytic leukemia were observed. Positive associations were indicated for cancers of the colon, bladder, breast, and uterine corpus. Cancers of the pancreas, prostate, and ovary, as well as the lymphomas did not show a strong association with socioeconomic status. Among blacks negative associations were demonstrable for cancers of the esophagus, lung, and uterine cervix, but not for stomach cancers. A positive association was observed for breast.